The present invention relates to hydromotive assemblies for hydroelectric plants or pumped storage plants and more particularly to a submersible hydroelectric assembly and to an energy storing dam adapted to receive it.
Hydromotive assemblies for hydroelectric production plants and pumped storage plants are, obviously, well known in the art.
The aim of such hydromotive assemblies, positioned at the inlet or outlet of the water passages engineered through hydraulic structures such as dams, is to convert the inherent gravitational energy of the water stored in the reservoir behind the dam into electric energy. The efficiency of this conversion is particularly important in low-head hydroelectric plants.
It is known that in a hydroelectric station the highest efficiency is attained when the hydraulic passages which directs the water flow through the dam are shaped like rectilinear embodiments. If these passages have bands, scrolls, elbow draft diffusers; the efficiency of the energy conversion is reduced because of increased friction between the water flowing through them and the inner surfaces thereof, thus reducing the amount of energy output of the hydroelectric station.
Furthermore, the erection costs of these civil engineered structures with such complicated water passages is highly expensive and puts a great financial overburden on the respective enterprises. There are also, great constructive delay involvements on these engineered projects before putting them in the commissioned operative status.
It is also known, that the best hydroelectric station engineered project must be designed under standardized concepts and mass produced industrial components. Furthermore, under operational performance, the concerned hydroelectric station must not have shutdown delays for cause of maintenance procedures on generators and turbines.
It must have also, a low investment cost figure in terms of money invested per kW. of installed capacity.
Additionally, the erection time schedule required to install turbines and generators and put them in operation must be the shortest possible one. All these objectives are claimed to be made possible by means of the present invention.
All these considerations which not only take into account hydraulic efficiency but also financial requirements, have not been fulfilled because the technology in low-head hydroelectric generation has not been advanced enough in efficient terms in recent years, to keep pace with the most spectacular and massive nuclear electric generation developments.
Consequently, less efficient design concepts and erection methods are used today although they are very expensive and produce very large engineered structures, requiring great delays in commissioning them.
It is an aim of the present invention to enable the provision of optimum erection methods by providing means for manipulating, positioning and mounting hydroelectric equipments with relative ease and in a very short time, in spite of the cumbersome sizes and heavy weights.
An additional aim of the present invention has been to provide a novel engineering approach in design technology whereby it is possible to increase the erection speed of a known hydroelectric project, thus minimizing the time delays to be supported until the commissioning date.
Because of their inherent modernizing trend and cost reducing concepts with mass produced interchangeable components to be introduced in hydroelectric plant construction designs, horizontal axis capsule-mounted generators with propeller fixed blade turbines or reversible Kaplan turbines acting as motive machines, which today are limited to very low-head hydroelectric projects; will be progressively installed in higher heads and fully involved in this novel technique, thus flexibilizing actual engineering trends in hydroelectric station designs and providing a better and more efficient tool for massive electric power interchanges purposes.
This statement is also applied to the tubular turbine with a peripheral rim mounted generator, first invented by the American Engineer Leroy F. Harza some 50 years ago.
An even further aim of the present invention has been to provide a novel engineered arrangement whereby hydraulic structures already built for other purposes such as: flood control dams, navigation development systems, irrigation intakes, abandoned dikes etc., can be easily converted into hydropower generating plants.
A further aim of the present invention has been to provide a new technique designed to modernize actual hydroelectric station operational procedures by means of the provision of reversible motor-generator equipment designed to be positioned against sluices and flow outlet structures.
By means of this arrangement, the electric power pattern belonging to the electric output of these hydrostations, is flexibilized following a combind output-input electric power interchangeable modified methodology.
This technical fact, permits modernization of obsolete hydrostations, at a very reduced cost.
According to one aspect of the present invention there is provided a substantially hydromotive assembly for an energy transformation purpose to be fitted against the structural body of a dam, in coincidence with the gated water passages embodied in the dam structure. In the general arrangement, the submersible hydromotive assembly is positioned upstream of the dam. It has incorporated a water conduit in the structural body, defined by a lateral wall surrounding the hydromotive machine and having a first open end for water admission and a second open end for discharging water entering the first open end. Auxiliary means are available for purposes of water flow control and water flow regulation as it is well known in the art.
This submersible hydromotive assembly is provided with, at least, one chamber defined in said lateral wall and of a volume at least sufficient to cause sinking or floatation of said hydromotive assembly when the former is filled with liquid or gas, respectively. Means are also provided for filling the chamber with liquid for sinking purposes or with gas for floatation purposes.
Another method for providing sinking or floatation of the hydromotive assembly is by means of incorporable or removable ballast weights positioned around the structural body of said hydromotive assembly.
This structural body incorporates also, a machine hall which includes the required equipment for the proper operational performance of said hydromotive assembly, such as: turbine governors, generator controls, compressed air systems, lubrication circuits and treatment systems, water refrigeration and treatment systems, emergency energy sources, self propulsion for auto-navigation, man-living facilities; and so on.
According to an even further aim of the present invention a new concept in engineering design of hydroelectric plants which flatly avoids the machine hall and related powerhouse structures incorporated at the dam, is provided. This novelty in engineering design produces a highly standardized criteria for dam designs and dam construction procedures, mainly because the simplification provided by the suppression of the expensive and difficult to build machine hall.
Maintenance of motive machines is simplified too. Machines which require important overhauls are instantly shifted away and replaced by operative-ones arriving from the servicenter. In this way, a unique service station is provided for the maintenance of a plurality of hydroelectric stations, thus revolutionizing maintenance concepts.
According to an even further aspect of the present invention, a method is provided for submerging and positioning a hydromotive assembly against a dam having means for producing control of water discharges through it, and having means for positioning and securing said submersible hydromotive assembly, upstream or downstream of said dam.
The method comprising the steps of: a). Taking a hydromotive assembly having a structural body, a water inlet and a water outlet and at least one chamber defined in said structural body; b). Floating the hydromotive assembly slighty upstream of said dam and so oriented that the longitudinal axis of said body and which extends through said water inlet and outlet, is parallel to the axis of said water directing means of the dam and positioned substantially thereabove; c). Introducing a liquid into said chamber to cause sinking of said submersible hydromotive assembly; d). Directing the sinking hydromotive assembly until it slighty rests on the bottom slab. e). Displacing the hydromotive assembly along the supporting slab to position its water outlet against the inlet of the water directing means engineered through the body of the dam. This sequence is produced by means of cables trained by cranes, winches, or by jacking arrangements, or other devices well known in the art. f). Securing the hydromotive assembly in such working position.
Although references in the specification are applied to rectilinear turbine-generator arrangements, it will be obvious to those skilled in the art that the teachings of the present invention are independent of the specific linear arrangement of both machines, and that such teachings are also applicables to hydromotive assembly arrangements in which such geometric spatial configuration follows any desired pattern.